1,1

The terms are consecutive 12-tuples, ordered so that (A) a(12i-11) < a(11i-10) < ... < a(12i) for i > 0, and (B) a(12i+1) < a(12i+13) for i >= 0. This sequence has primitive solutions only. If k is relatively prime to all of the terms in a primitive 12-tuple, then multiplying the terms in that 12-tuple by k gives another solution.

38848397472, 38850486624, 39955028960, 41002131936, 41266440252, 41271882804, 41273232372, 42433832980, 42439669580, 42441951860, 43545898068, and 44591929866 have the same value of phi (12070840320), sigma (121347072000), and tau (384), so these twelve numbers are in the sequence.

Cf. A134922, A322687, A322688, A322689, A322690, A322691, A322692, A322693, A322694, A322695, A322696, A322697.

Sequence in context: A234072 A112446 A295460 * A216018 A256842 A225886

Adjacent sequences: A306427 A306428 A306429 * A306431 A306432 A306433

nonn,tabf,more

Jud McCranie, Feb 14 2019

approved